gr5

Make sure the nozzle isn't clogged maybe? Although it's not a disaster if it is. You could heat nozzle to 200C and pass some PLA through it with the "move material" feature. don't keep it hot for more than a few minutes though.

Shipping can be vicious! Make sure the 4 feet sit on a flat surface without rocking. Sometimes it is so warped that two of the top corners are significantly higher than the other 2 corners and so it prints instead of in a flat plane, it prints in a saddle shape along the diagonal. It's difficult to make the glass into the same shape (but you can do it by putting washers under 2 corners).

Nice work! My first comment has nothing to do with your question - just that you should be aware that leaving PLA or ABS in the nozzle at 250C for 30 minutes can easily cook it into a solid block that is difficult to get out without disassembly. So I would have done this test at 180C. But anyway getting to your problem. There is a possible software solution and of course the obvious hardware solution is to use a shielded cable. I prefer the hardware solution. You can just cut the existing connectors off the existing fan cable and leave an inch of cable at each end and strip that and solder to a shielded cable - of course you need to use some kind of insulation such as heat shrink tubing to avoid shorting out the fan signal. software solution: http://marlinbuilder.robotfuzz.com/ If you go here - there is a checkbox (5th from the bottom) called "increase pwm frequency". This supposedly can help your issue. I believe this is "checked" by default in the latest UMO builds but I'm not sure. It can make it more likely that your darlington transistor that controls the fan overheats and blows out but I have been using it like that (with fan running at 30% often) and had no problems so far. However that transistor (Q1 I think?) does blow up often for many people. It's very cheap and very easy to replace if you have even mild soldering skills (cut the leads at the device so you have something to pull on with pliers when you melt the solder). Anyway that Marlin builder is an excellent one - extremely easy to create the hex file and then you can upload it into your printer using Cura "expert" "load custom firmware...".

I see your point - your image shows a layer height equal to the nozzle width. That's why Cura doesn't recommend layer height > 3/4 of the nozzle width (.4mm nozzle means .3mm layer height max). But if the layer height is too small you have a problem also - so .05mm layer height isn't going to carry enough heat to melt the layer below. I would think a .2mm layer height would give you the most melting without worrying about air/contact. The bead of plastic being laid down would be pretty close to rectangular.

I see you are in the USA joshh. You can get a new temp sensor from met at gr5.org/store or get an official UM one from fbrc8.com. fbrc8.com might even send you a free one if you ask nicely. My store may say I'm out but I expect a shipment to arrive Tuesday.

I would think that a thicker layer would bond better because there is more heat stored in that thicker trace going down on top of the layer below. You don't have to melt the entire layer below - just the top surface. I also found that printing at 255C was hot enough to cause a nozzle clog and if I print that hot I need to speed up my printing a bit. It was more than a nozzle clog - it was the bottom 10mm of filament that turned into a cooked glob that would not melt.

I don't think the opto endstops require any changes to the firmware. Or worst case it just reverses the endstop logic (it's a field in the Configuration.h file).

It's probably all caused by a single loose wire - but I have no idea which wire.

Ug. Where do I start. Well - I don't recommend Ultimaker for this. The Envision Tec uses a different technology (resin printer that uses light to harden the resin) that is about 10X higher resolution than Ultimaker technology (melting plastic and squirting through nozzle). The Ultimaker has 20 micron resolution ONLY IN THE Z Axis. The X and Y axis are limited to the nozzle radius which by default is 200 microns. You can get a little better - possibly down to 125 microns but that's about it for this technology. Look at the b9creator or the Form1. Google those printers. Particularly the b9creator.

It may have simply been a loose wire and moving the printer around fixed it.

Oh please do post a picture - on this topic: https://ultimaker.com/en/community/view/1467-post-your-latest-print And then go to the end of the topic and look at a few recent amazing prints.

To contact support start with support.ultimaker.com. Who sends you the spare temp sensor will depend on where you bought the printer and what country you live in.

You can check the temp probe by simply turning it on and it will complain if it is completely broken, then go to MAINTENANCE ADVANCED and go to nozzle temp and make sure it is at room temp (around 20C). Then you can test the heater by turning *that* on but only for 5 seconds as you should be careful. The block should then feel warm to touch even after only 5 seconds of heating. To test the fans, the rear fan usually comes on upon power up (but not newer models whcih come on when nozzzle gets > 40C). The side fans are tested by selecting "PRINT" then choose any random model then immediately go to TUNE menu (and potentially turn off heat to bed and nozzle) and turn on the fans there. Just cut power when you are done testing as exiting the TUNE menu may have the printer start trying to print.

I have to admit my ABS prints also tend to be weak. I am an expert at PLA and can get pretty much perfect prints every time but ABS frustrates me and tends to clog my nozzle if I print too hot and tends to have bad layer bonding if I print too cold. I guess I just need to print hotter and faster maybe. When I print ABS I feel like I just got the printer and am helpless. When I say "weak" they are strong enough for most things but tend to be not as strong as my PLA parts. Almost as strong, but not quite as strong.

Did you check on the cooling issue? Put your printer on it's side and have a desk fan blow on the board. It prints sideways just fine. Those pictures are helpful. It is a large skip and always the same direction and most layers are fine. Look the issue is most likely: 1) Pulley slipping 2) Friction 3) hot stepper driver 4) end stop switches 5) crosstalk? did you put marks on all 6 of the pulleys for the bad axis? Or only 4? It's almost always one of the 2 pulleys on the short belt. 90% of the time. Are you absolutely sure this isn't the problem? You need to eliminate all of the above until you figure it out. Hot stepper driver is easy to test by using fan. end stop switch -- I would test this by hitting switch ON PURPOSE and see if a message comes up on the display and see if the behavior is the same or different. If the behavior is identical (no message on screen in both cases) then we haven't proved it's limit switch but haven't eliminated it either - also you can figure out *which* switch it is by the direction it moves because each switch would affect a different direction and one of the switches is TOTALLY USELESS so just disconnect that one please. The one not used for homing. crosstalk - yikes - I never head of this - I guess reseat the cables? Put some tape between the tables maybe to keep signals farther apart? Friction - is one axis much much higher friction than the other? Push head around with power off. Sometimes if the long belts are too tight or much more likely if the end caps are pushing too hard on the rods you get very high friction and the stepper motor can skip steps. This seems unlikely in your case but the quick check is toosen the end caps a bit for the 2 thick rods on the bad axis. Only one endcap for each axis. Think of this as a fun puzzle! Don't let it depress you!

Please show a photo. In your later post you indicate that the bottom layer looks good but that later it comes off? Is that what you mean? Corners lifting? How big is this part. You ask about one issue but I think maybe you are having a different issue.

Also consider testing the raw filament. I know they are different diameters. The 3mm should be as strong as 2.65 strands of 1.75mm filament - so stronger than 2 strands of 1.75 and weaker than 3. Test that with a pull test. You could loop the filament over a ceiling hook, stand on a scale and slowly pull harder and harder until it breaks. Repeat with the ultimaker filament. Keep careful records. This will test to see if (unprinted) the filaments are not roughly the same strength. Usually a difference in strength of 2X is considered minor or small. I know - seems crazy. But I've seen some filaments 10X stronger/weaker than others.

I find 240C to be too cold for ABS. The layer adhesion is lousy at 220C but much better at 240C. But still not good enough. If you pay careful attention, it should be breaking along layer boundaries. If that is true then the problem is most likely you should be printing hotter. Not all temp sensors are equal so 230C on mbot might be the same temp as 250C on U2. Also the temp sensors on the U2 sometimes (like 1 in 10 temp sensors) read as much as 10C high (meaning they print 10C cool). So try printing at 250C. Also .3mm is quite thick for a .4mm nozzle. You should consider getting a larger nozzle if you need to print this fast or consider slowing it down a bit. I'm not sure how viscous ABS is at 230C but it seems to me it might be underextruding quite a bit. Don't do 100% infill. It doesn't really add much strength. Strength of most parts is in the walls, not the center. That's why bones (among other structural things) are hollow. That's why it's okay for a plumber to drill a hole right through the center of a joist but if they cut a notch in the edge the building inspector will make the carpenter put in a new joist. Of course this is just a general rule - it depends on the shape of the part. For something like a pencil shape 100% infill *is* stronger. Anyway I suspect you aren't getting the layer adhesion on the U2 that you are getting on the mbot due to insufficient heat.

Oh wait - UMO+. No bottom fan. Add a fan temporarily to see if that helps - the printer will print on it's side (or even upside down) just as well (no better or worse really) than rightside up.

Why did you set it to .42mm nozzle? That won't do anything if shell is .4mm or .8mm so it doesn't really matter. Although if shell is thick enough it will do strange things.

UMO porn!

These problems all seem to happen around the same height. So I am going to go with overheating. If the stepper driver overheats this will happen also - this would make complete sense. Check your bottom fan! Consider printing with the printer on it's side and add an extra fan or something. Is your house hotter this summer than it was when the printer was last working? Maybe a heat sink fell off the Y stepper driver.

Well then those pictures aren't helpful. I'm confused - why would there be a rats nest just because it shifted. Doesn't it just keep printing upwards but over to the side? endstops - if the endstop is triggered then that servo is told not to move any farther in that direction but it's okay to go the other direction. So you get a shift. It could be triggered by an electrical short or a bad switch, or something mechanical bumping the switch. You could just unplug the switches for that axis. The homing procedure will be horrible and noisy. You could hit the switch mid print just to see what happens - see if you get a message on the ulticontroller.

cold pull porn! Those are perfect!

Please update your profile to specify if you have a UMO or UM2 or other. Also update your location settings to indicate your country. Can you take a video of this flicker/shake? Under 10 seconds if possible.